Fix issues with Pinboard formatting

I was having issues with the Pinboard logger accidentally running items together. This would result in a blob of text that looked something like this:

````
## Pinboard bookmarks

#### [Pinboard (jeffmueller)](https://pinboard.in/u:jeffmueller/)

* [No, Rails' CookieStore isn't broken – Coffeepowered](https://coffeepowered.net/2013/09/26/rails-session-cookies)

        No, Rails' CookieStore isn't broken http://bit.ly/16HqTxn (http://bit.ly/19IVhUx) via @thibaut_barrere* [Logout is broken by default in Ruby on Rails Web applications | MaverickBlogging](http://maverickblogging.com/logout-is-broken-by-default-ruby-on-rails-web-applications/)

        CookieStore vulnerability in Rails 2.x, 3.x, 4.x. http://bit.ly/16HqURM (http://bit.ly/19IViHV)* [Revisiting All My Past Product Reviews and Recommendations: What Stuck and What Didn’t? — Shawn Blanc](http://shawnblanc.net/2013/10/revisiting-reviews-and-recommendations/)
* [API first architecture or the fat vs thin server debate](http://www.leaseweblabs.com/2013/10/api-first-architecture-fat-vs-thin-server-debate/)
* [The Science behind GTD](http://facilethings.com/blog/en/science)

        RT @FacileThings: The Science behind GTD http://bit.ly/17zjrjx #gtd #productivity | Proud of @gtdguy 's comment :)* [Wasted Time](http://the-northwind.com/blog/2013/10/9/wasted-time)
* [Wallflowers: my favorite OS X augmentations - BrettTerpstra.com](http://brettterpstra.com/2013/10/12/wallflowers-os-x-augmentation/)

#social #bookmarks
````

You can see that the issue is with items that are saved with a summary. This fixes the formatting issues that were occurring. I've been running it for over a week now, and none of the resulting entries have been ill-formatted.